The transmission of light through a transparent solid can be described by the equation:
IT = I0(l - R)2e-BL
where IT is the transmitted intensity, I0 is the intensity of the incident beam, B is the absorption coefficient, L is the length of the transparent solid, and R is the fraction of light which is reflected at the interface. If the light is normal to the interface and the beams are transmitted through air, R = (n €“ 1/n €“ 1)2 where n is the index of refraction for the transparent solid. Experiments measuring the intensity of light transmitted through specimens of a transparent solid of various lengths are given in the following table. The intensity of the incident beam is 5 watts/m2.

Use this data and curve fitting to determine the absorption coefficient and index of refraction of the solid.

L (cm) 1.2 1.7 22 4.5 6.0 24.2 4.0 3.8 3.6 2.9 2.5 0.5 I7 (watts/m-)